<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>rectangle</title>
  <link rel='stylesheet' href='./layout.css'>
</head>
<body>
  <h1>hello cmt </h1>
  <form id="main">
    <label>宽度</lable>
      <input type="number" min="0" autofocus required step="0.01" id="width"><span></span>
    <br>

    <div id="width-err"></div>

    <label>高度</label>
    <input type="number" min="0" required step="0.01"  id="height"> <span></span>   <br>

    <div id="height-err"></div>
    
  
    <input type="submit" id="calc" value="计算">
    <br>
    <label>周长</lable>
    <input type="text" id="perimeter" disabled>
    <br>
    <label>面积</lable>
    <input type="text" id="area" disabled>
    <br>
  </form>

  <script src='//apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js'></script>
  <script src='./main.js'></script>
</body>
</html>
